Oil filter and method of manufacturing the oil filter

ABSTRACT

An oil filter for preliminarily confirming a correct assembling of a valve body to a holder and for preventing the valve body from being abnormally assembled. A valve seat  22  is welded to a cap  14  covering a filter element  12 . A claw portion for a valve body  25   e  is formed on the valve body  25 , and an engagement portion for the valve body  27   e  to be engaged with the claw portion for the valve body  25   e  is formed on a holder  15  assembled with the inner peripheral side of the filter element  12 . In addition, a spring member  29  is fitted between the valve body  25  and a spring receiving portion  27  provided for the holder  15 . By the engagement of the claw portion for the valve body  25   e  with the engagement portion for the valve body  27   e , the valve body  25  is assembled with the holder  15.

CROSS REFERENCE TO RELATED APPLICATION

This is the 35 USC 37 national stage of International ApplicationPCT/JP01/11392 filed on Dec. 25, 2001, which designated the UnitedStates of America.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an oil filter for filtering an internalcombustion engine oil of such as automobile, and more particularly, toan oil filter provided with a relief valve which operates at a time whena filter element clogs.

BACKGROUND ART

The applicant has provided an oil filter provided with a relief valveshown in FIG. 4 (refer to Japanese Patent Application No. HEI 11-92540).This oil filter comprises a filter element 1 having an annular structurethrough which oil passes, a cap 2 having substantially a cylindricalshape and covering an outer periphery of the filter element 1, a holder3 fitted into the inside of the filter element 1, and a relief valve 8which operates at a time when the filter element is clogged. In thisFIG. 4, a base of the oil filter to be mounted to an engine side is notillustrated.

A valve seat 4 constituting a relief valve 8 is welded to an innersurface of a top portion of the cylindrical cap 2. This valve seat 4 isformed with a claw portion 4 b to be engaged with an upper end portion 3a of the holder 3. And a valve body 5 is mounted to the lower surface ofthe valve seat 4. The valve body 5 is urged against the valve seat 4 bya coil spring 6, which is disposed between the valve body 5 and a springreceiving portion 7 formed on the holder 3.

In an occurrence that the filter element 1 clogs and pressure differencebetween a dirty side and a clean side is more than a predeterminedpressure, the valve body 5 is depressed against a spring force of thecoil spring 6. According to this action, the oil passes around thefilter element 1 and passes through an oil passage 4 a opened to thevalve seat 4.

DISCLOSURE OF THE INVENTION

In the oil filter mentioned above, the valve seat 4 is preliminarilywelded to the cap 2, and then, the valve body 5 and the coil spring 6are assembled to the valve seat 4. Thereafter, the claw portion 4 b ofthe valve seat 4 is engaged with the holder 3.

However, at the time when the claw portion 4 b of the valve seat 4 isengaged with the holder 3, there is a fear that the coil spring 6 mayshift from a predetermined position and ride on an upper end of thespring receiving portion 7 or a fear that the valve body 5 may getcaught in the valve seat 4 and then be assembled with the valve seat 4in an inclined state. Furthermore, since it is impossible to visuallyobserve the valve seat 4, the valve body 5, and the coil spring 6, etc.from the outside of the cap 2, such abnormal assembling or assembledstate cannot be confirmed after these are assembled. Furthermore, itrequires careful and difficult work to engage the claw portion 4 b ofthe valve seat 4 to the holder 3 while maintaining the state that thevalve body 5 and the coil spring 6 are normally assembled.

An object of the present invention is, therefore, to provide an oilfilter capable of visually observing the assembling or assembled stateof the valve body and the like to the holder to thereby prevent anincorrect or abnormal assembling thereof.

The present invention will be described hereunder.

Further, it is to be noted that, in the following description, althoughreference numerals described in the drawings accompanied are added withparenthesis, the present invention should not be defined to onedescribed in the drawings.

In order to achieve the above object, the inventor of the subjectapplication preliminarily assembled a valve body and a spring member toa holder, and after confirmation of correctly assembled state of thevalve body with respect to the holder, a valve seat was assembled to theholder. More specifically, the above object is achieved by providing anoil filter, which comprises a cap (14) covering an annular filterelement (12), a holder (15) disposed in an inner peripheral side of thefilter element (12), a valve seat (22) mounted to the cap (14), a valvebody (25) being movable in an axial direction of the holder (15) so asto abut against the valve seat (22), and a spring member (29) disposedbetween a spring receiving portion (27) formed on the holder (15) andthe valve body (25), wherein either one of the holder (15) and the valvebody (25) is formed with a claw portion for the valve body (25 e) andanother one of the holder (15) and the valve body (25) is formed with anengagement portion for the valve body (27 e) to be engaged with the clawportion for the valve body (25 e), and when the claw portion for thevalve body (25 e) is engaged with the engagement portion for the valvebody (27 e), the valve body (25) is assembled with the holder (15).

According to this invention, the valve body and the spring member can bepreliminarily assembled with the holder, and after the confirmation ofthe correctly assembled state of the valve body which is movable in theaxial direction with respect to the holder, the valve seat mounted tothe cap can be assembled to the holder. Thus, the valve body and thespring member can be prevented from being abnormally assembled.

Further, in one preferred example, the valve body (25) is provided witha valve portion (25 a) abutting against the valve seat (22), a wallsection (25 d) disposed on a side of the valve portion (25 a) oppositeto a side where the valve portion (25 a) abuts against the valve seat(22) and extending in the axial direction of the holder (15), and theclaw portion for the valve body (25 e) formed on a front end portion ofthe wall section (25 d), and the claw portion for the valve body (25 e)is engaged with the engagement portion (27 e) formed on the springreceiving portion (27).

According to this invention, since the claw portion formed on the valvebody engages with the engagement portion of the holder, the valve bodycan be prevented from being come off from the holder.

Furthermore, according to one preferred example, the spring receivingportion (27) is formed with a guide hole (27 c) into which the wallsection (25 d) is inserted so that the movement of the wall section (25d) in the axial direction of the holder (15) is guided by an innerperipheral surface of the guide hole (27 c).

According to this invention, since the wall section of the valve body isguided by the inner peripheral surface of the guide hole, the valve bodycan be surely moved in the axial direction with respect to the holder,and in addition, an oblique mounting of the valve body to the holder canbe prevented.

Furthermore, in one preferred example of the present invention, eitherone of the holder (15) and the valve seat (22) is formed with a clawportion for the valve seat (22 e) and another one of the holder (15) andthe valve seat (22) is formed with an engagement portion for the valveseat (15 c) to be engaged with the claw portion for the valve seat (22e), and when the claw portion for the valve seat (22 e) is engaged withthe engagement portion for the valve seat (15 c), the valve seat (22) isassembled with the holder(15).

According to this invention, the cap, the relief valve and the holdercan be integrated, and the filter element can be easily taken out fromsuch integrated structure.

Still furthermore, the above mentioned objects can be achieved accordingto the oil filter manufacturing method of the present invention, whichcomprises the steps of engaging a valve body (25) with a holder (15) tobe disposed in an inner peripheral side of a substantially annular oilfilter (12) and assembling, to the holder (15), the valve body (25) anda spring member (29) disposed between the holder (15) and the valve body(29) and the steps of engaging a valve seat (22) which abuts against thevalve body (25) with said holder (15) and assembling the valve seat (22)to the holder (15).

According to this aspect, the valve body and the spring member arepreliminarily assembled with the holder, and after the confirmation ofthe valve body which is correctly assembled and movable in the axialdirection with respect to the holder, the valve seat mounted to the capcan be assembled to the holder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an oil filter according to oneembodiment of the present invention.

FIG. 2 is a sectional view of a relief valve of the oil filter of FIG.1.

FIG. 3 is a sectional view showing an oil filter according to anotherembodiment of the present invention.

FIG. 4 is a sectional view (partially including a side view) showing anoil filter of conventional structure.

BEST MODE FOR EMBODYING THE INVENTION

FIG. 1 illustrates one embodiment of the oil filter of the presentinvention. This oil filter comprises a housing 11 and a filter element12 housed therein. The housing 11 is composed of a base 13 to be mountedto an engine side of an automobile or like and an approximatelycylindrical cap 14 so as to provide a sealing container structure. Onthe inner peripheral side of the filter element 12, there is provided aholder 15 for holding the filter element 12. A relief valve 16 isdisposed on the upper portion of the holder 15, the relief valve 16being opened in accordance with pressure difference more than apredetermined value.

The base 13 comprises an upper cylindrical portion 13 a and a lowermanifold portion 13 b. A female screw thread to be screw-engaged withthe cap 14 is formed on the upper end side in the inner peripheralportion of the cylindrical portion 13 a. The manifold portion 13 b isformed with a flow-in passage 17 into which dirty oil exhausted from theengine flows and a flow-out passage 18 through which clean oil filteredby the filter element 12 flows out. One end portions of the flow-in andflow-out passages 17 and 18 are opened to a mounting surface 13 c of thebase 13 to be mounted to an engine block and other end portions thereofare opened inside the cylindrical portion 13 a.

The cap 14 is a mold product of a resin material and comprises asubstantially disc-shaped base bottom portion 14 a and a cylindricalside portion 14 b. The side portion 14 b is formed, at its front endside, with a male screw thread and formed, on an outer peripheralsurface thereof, with a flange 14 c. The cap 14 and the cylindricalportion 13 a of the base 13 are engaged together through thescrew-engagement between the male screw thread of the cap 14 and thefemale screw thread of the base till the flange 14 c abuts against theend surface of the cylindrical portion 13 a. Further, an O-ring 19 isfitted, at the outer periphery of the cap 14, between the flange 14 cand the male screw thread portion. This O-ring 19 closely contacts theinner periphery of the cylindrical portion 13 a to thereby seal ajoining portion of the cap 14 and the cylindrical portion 13 a of thebase 13.

The filter element 12 having substantially the tubular or annular shapeis formed by folding and bending, in zigzag shape, a predeterminedfiltering member so as to have a number of gussets or ribs. Seal memberssuch as hot-melt which clogs openings formed between the gussets aredisposed to both end portions of the filter element 12, and aring-shaped seal plate is joined.

A holder 15 is arranged inside the filter element 12, and the holder 15is a mold product of a resin material having approximately a cylindricalshape. Further, this holder 15 is composed of a pair of cylindricalportions 15 a, 15 a disposed at both longitudinal end portions thereof,a plurality, for example, four, vertical ribs extending in the axialdirection of the holder 15 so as to connect the cylindrical portions 15a, 15 a and a plurality of horizontal ribs arranged between thecylindrical portions 15 a, 15 a with equal interval.

The filter element 12 is disposed to be coaxial with the holder 15 byfitting the same to the outer peripheral portions of the vertical andhorizontal ribs. Furthermore, the cylindrical portion 15 a on the lowerside, as viewed, is fitted to an expanded portion 18 a of a flow-outpassage 18. According to the structure mentioned above, the holder 15and the filter element 12 held by the holder 15 are positioned to becoaxial with the cylindrical portion 13 a of the base 13.

As shown in detail in FIG. 2, the base end portion (upper end portion inFIG. 1 or 2) 14 a of the cap 14 is formed with a plurality ofprojections 21, 21 - - - extending downward and having downward ends towhich a valve seat 22 is joined by joining means such as ultrasonicwelding or like. These projections 21 are formed with openings 21 athrough which oil flows into a space defined by the valve seat 22 andthe base end portion 14 a.

The valve seat 22 is provided with a disc-shaped member 22 a having anoil passing port 22 b formed on the central portion of the plate member22 a and a fitting portion 22 c extending downward, as viewed in FIG. 2,from a lower surface of the plate member 22 a and fitted to the uppercylindrical portion 15 a of the holder 15. The fitting portion 22 c issectioned by slits 23 into a plurality of wall sections 22 d, 22d, - - - , and each of the wall sections 22 d is provided, at its frontend (lower end), with a claw portion for the valve seat 22 e. The clawportion for the valve seat 22 e has a wedge shape tapered inward fromupper end to lower end of the valve seat 22. The claw portion for thevalve seat 22 e is engaged with the lower end surface of the cylindricalportion 15 a of the holder 15 as a portion 15 c to be engaged for thevalve seat 22.

As the valve seat 22 is fitted to the cylindrical portion 15 a of theholder 15, the wall sections 22 d, 22 d, - - - are gradually flexed anddeformed, and the wall sections 22 d, 22 d, - - - are restored in theirpositions at the time of the claw portion 22 e of the valve seat 22being engaged with the lower end surface of the cylindrical portion 15a. At an instance that the claw portion 22 e for the valve seat is onceengaged with the lower surface of the cylindrical portion 15 a, thevalve seat 22 cannot be easily come off from the cylindrical portion 15a even if any force for pulling the valve seat 22 from the cylindricalportion 15 a is applied.

Further, although, in the described embodiment, the claw portion 22 e isformed on the valve seat 22 and the engagement portion 15 c to beengaged with the claw portion 22 e is formed on the holder 15, it may bepossible to form the claw portion to the holder 15 and form theengagement portion to the valve seat 22.

A valve body 25 is disposed in the inside of an upper end portion of theholder 15, as shown in FIGS. 1 and 2. The valve body 25 is provided witha valve portion 25 a having substantially a disc shape abutting againstthe valve seat 22 and a fitting portion 25 b disposed on a side of thevalve portion opposite to a side where the valve portion 25 a abutsagainst the valve seat 22 so as to be fitted to the holder 15.

The fitting portion 25 b is sectioned by slits 25 c into a plurality ofwall sections 25 d, 25 d, - - - extending axially and being flexed ordeformed, and each of the wall sections 25 d is provided, at its frontend (lower end), with a claw portion for the valve body 25 e. The clawportion for the valve body 25 e has a wedge shape tapered inward fromupper end to lower end of the valve body 25. The claw portion 25 e forthe valve body is engaged with a lower surface of a spring receivingportion 27 formed on the holder 15 as an engagement portion 27 e to beengaged. The detail of the spring receiving portion 27 will be describedlater.

As the valve body 25 is fitted to the spring receiving portion 27, thewall sections 25 d, 25 d, - - - are gradually flexed and deformed, andthe wall sections 25 d, 25 d, - - - are restored in their positions atthe time when the claw portion 25 e of the valve body 25 is engaged withthe lower end surface of the spring receiving portion 27. At an instancethat the claw portion 25 e of the valve body 25 is once engaged with thelower surface of the spring receiving 27, the valve body 25 cannot beeasily come off from the spring receiving portion 27 even if any forcefor pulling the valve body 25 from the spring receiving portion 27 beapplied. That is, the valve body 25 can be prevented from being come offfrom the spring receiving portion 27 by the engagement of the clawportion 25 e for the valve body with the lower end surface of the springreceiving portion 27.

Further, although, in the described embodiment, the claw portion 25 e isformed on the valve body 25 and the engagement portion 27 e to beengaged with the claw portion 25 e formed on the spring receivingportion 27, it may be possible to form the claw portion 25 e for thevalve body to the spring receiving portion 27 and form the engagementportion to the valve body 25.

The spring receiving portion 27 for receiving a coil spring 29 isintegrally formed on the horizontal ribs of the holder 15. The springreceiving portion 27 is composed of a cylindrical bush 27 a and adisc-shaped spring support plate 27 b. The bush 27 a is formed with aguide hole 27 c through which a wall section 25 d of the valve body 25is inserted so that the axial movement of the wall section 25 d of thevalve body 25 is guided by the inner peripheral wall surface of theguide hole 27 c to thereby constitute the valve body 25 to be movable inthe axial direction.

A coil spring 29 as a spring member is mounted between the upper surfaceof the spring receiving portion 27 of the holder 15 and the lowersurface of the valve portion 25 a of the valve body 25.

Under the condition that the valve body 25 and the coil spring 29 areassembled to the holder 15, the valve body 25 is urged upward by theelastic force of the coil spring 29 and, then, the claw portion for thevalve body 25 e is engaged with the lower surface of the springreceiving portion 27. Furthermore, under the condition that the valveseat 22 is assembled to the holder 15, the valve seat 22 slightlydepresses the valve body 25 against the elastic force of the coilspring. Accordingly, the coil spring 29 is slightly compressed andslightly lowered from the position at which claw portion for the valvebody 25 e is engaged with the lower surface of the spring receivingportion 27. Then, the coil spring 29 urges the valve body 25 so that thevalve body 25 abuts against the valve seat 22.

The cap 14, the holder 15 and the relief valve 16 are assembled as asub-assembly in accordance with the manner which will be mentionedhereunder.

First, the coil spring 29 is set on the upper surface of the springreceiving portion 27, and the valve body 25 is then placed inside thecoil spring 29 and depressed till the claw portion for the valve body 25e is engaged with the lower surface of the spring receiving portion 27.Through this operation, the coil spring 29 is placed, in the compressedstate, between the spring receiving portion 27 and the valve body 25.Then, the claw portion for the valve body 25 e and the spring receivingportion 27 can be surely engaged with each other by the repulsion forceof the coil spring, and the valve body 25 is assembled to the holder 15.

In the next step, the valve body 25 is depressed against the coil spring29 to thereby confirm the correct operation and assembling state of thevalve body 25 and so on. After the confirmation that the correctassembling of the valve body 25 and the coil spring to the holder 15,the holder 15 is pushed so as to fit to the outer peripheral surface ofthe wall section 22 till the cylindrical portion 15 a of the holder 15substantially contacts the plate portion 22 a of the valve seat 22.According to this operation, the claw portion for the valve seat 22 e isfitted to the lower end portion of the cylindrical portion 15 a of theholder 15. At this time, the coil spring 29 is further slightlycompressed. The valve body 25 is pushed against the valve seat 22 by theelastic force of the coil spring 29 in the described state, and at thesame time, the claw portion for the valve seat 22 e is pushed againstthe lower surface of the cylindrical portion 15 a of the holder 15.According to such operation, the holder 15 and the valve seat 22 areprevented from being come off from each other in the axial directionthereof, and as a result, the cap 14, the holder 15, the valve body 25and the coil spring 29 are assembled integrally.

The filter element 12 is then mounted to the outer periphery of theholder 15 attached to the cap 14, and thereafter, the cap 14 isassembled with the base 13, so that the seal plates are tightlycontacted, at both the end portions of the filter element 12,respectively, to the seal receiving surface 13 d of the base 13 and theplate portion 22 a of the valve seat 22. Thus, the inside of the housing11 is defined into the dirty side communicating with the flow-in passage17 and the clean side communicating with the flow-out passage 18. Theoil flowing in the dirty side passes the filter element 12 in the radialdirection, then flows into the clean side, and thereafter, returns tothe engine through the flow-out passage 18. At an instance when thefilter element 12 clogs and a pressure difference between the dirty sideand the clean side in the housing exceeds a predetermined value, thevalve body 25 is separated from the valve seat 22 against the elasticforce of the coil spring 29, thus opening the oil passing hole 22 b.

At a time when it is required to change the filter element 12, the cap14 is removed from the base 13, and then, the cap 14, the relief valve16, the holder 15 and the filter element 12 are removed all at onceintegrally. Thereafter, the filter element 12 is drawn out from theholder 15 and then exchanged with another filter element.

FIG. 3 represents another embodiment of an oil filter according to thepresent invention. The filter element of this embodiment is similar tothe embodiment mentioned hereinbefore except for structures of the cap14, the valve seat 22 and the spring receiving portion of the holder 15,so that the similar structure is omitted in its explanation only withthe same reference numerals.

In this embodiment, a valve body 31 is composed of a disc-shaped valveportion 31 a abutting against the valve seat 22 and a fitting portion 31b disposed on a side of the valve portion 31 a opposite to a side wherethe valve portion abuts against the valve seat 22 and fitted to theholder 15. The fitting portion 31 b is sectioned, by slits 31 c, into aplurality of flexible wall sections 31 d extending in the axialdirection thereof, and claw portions for the valve body 31 e are formedon the front (lower as viewed) end portions of the respective wallsections 31 d.

Different from the aforementioned embodiment, in this embodiment, thereis formed, on a portion of the valve portion 31 a on the side abuttingagainst the valve seat 22, a protruded portion 31 f having cross-shapedsection projecting inside the oil passing hole 22 b opened to the valveseat 22. Further, a spring receiving portion 32 of the holder 15 is notprovided with a bush portion, which differs from the aforementionedembodiment, and the spring receiving portion 32 is composed of only adisc-shaped spring support plate. The spring support plate is formedwith a guide hole 32 a for guiding the wall sections 31 d of the valvebody 31.

The valve body 31 is guided to be movable in its axial direction at twoportions of the protruded portion 31 f and the wall section 31 d. Thatis, the protruded portion 31 f of the valve body 31 is guided by theinner peripheral surface of the oil passing hole 22 b formed on thevalve seat 22, and the wall section 31 d of the valve body 31 is guidedby the inner peripheral surface of the guide hole 32 a formed on thespring receiving portion 32. According to the structure of thisembodiment, the axial movement of the valve body 31 can be surely guidedwithout forming any cylindrical bush, for guiding the valve body, to thespring receiving portion 32.

Further, it is to be noted that the present invention is not limited tothe described embodiments and may be executed with other modifiedembodiments.

For example, it is not necessary for the spring receiving portion 27(32) to be formed integrally with the horizontal ribs of the holder 15and the spring receiving portion may be attached, for example, by meansof welding, to an optional position on the holder 15. Moreover, thefilter element 12 is not limited to a folded one having a zigzag shapeand employs many other shapes.

As mentioned hereinbefore, according to the present invention, the clawportion for the valve body is provided for either one of the holder orthe valve body and an engagement portion for the valve body is providedfor the other one thereof so as to be engaged with the claw portion forthe valve body, and by the engagement of the claw portion for the valvebody with the engagement portion for the valve body, the valve body isassembled with the holder. According to this structure, after thepreliminary assembling of the valve body and the spring receivingportion and the confirmation of the axial movement of the valve bodywith respect to the holder, the valve seat can be assembled to theholder.

1. An oil filter comprising: a cap covering an annular filter element; aholder disposed in an inner peripheral side of said filter element; avalve seat mounted to said cap; said valve seat having a plate memberand an oil passing hole extending through the plate member; a valve bodybeing movable in an axial direction of said holder so as to abut againstsaid valve seat; said valve body having a protruded portion formed on aside abutting against the valve seat; said protruded portion projectingthrough the oil passing hole of the valve seat so that the protrudedportion is guided by the oil passing hole, and penetrates from a lowerside of the plate member past an upper side of the plate member; and aspring member disposed between a spring receiving portion formed on saidholder and said valve body, wherein either one of said holder and saidvalve body is formed with a claw portion for the valve body and anotherone of the holder and the valve body is formed with an engagementportion for the valve body to be engaged with said claw portion for thevalve body, and when said claw portion for the valve body is engagedwith the engagement portion for the valve body, the valve body isassembled with the holder, and either one of said holder and said valveseat is formed with a claw portion for the valve seat and another one ofthe holder and the valve seat is formed with an engagement portion forthe valve seat to be engaged with said claw portion for the valve seat,and when said claw portion is engaged with the engagement portion forthe valve seat, the valve seat is assembled with the holder.
 2. An oilfilter according to claim 1, wherein said valve body is provided with avalve portion abutting against the valve seat, a wall section disposedon a side of the valve portion opposite to a side where the valveportion abuts against the valve seat and extending in the axialdirection of the holder, and the claw portion for the valve body formedon a front end portion of said wall section, and said claw portion forthe valve body is engaged with said engagement portion formed on saidspring receiving portion.
 3. An oil filter according to claim 2, whereinsaid spring receiving portion is formed with a guide hole into whichsaid wall section is inserted so that movement of the wall section inthe axial direction of the holder is guided by an inner peripheralsurface of said guide hole.
 4. A method of manufacturing an oil filtercomprising the steps of: engaging a valve body with a holder to bedisposed in an inner peripheral side of a substantially annular oilfilter; assembling, to said holder, said valve body and a spring memberdisposed between the holder and the valve body; providing a valve seathaving a plate member and an oil passing hole extending through theplate member; engaging the valve seat which abuts against the valve bodywith said holder, while a protruded portion of the valve body projectsthrough the oil passing hole of the valve seat so that the protrudedportion is guided by the oil passing hole, and penetrates from a lowerside of the plate member past an upper side of the plate member; andassembling said valve seat to said holder.